1. Technical Field
The present disclosure relates to a hydrogen generator and a fuel cell system both incorporating a hydro-desulfurizer that removes sulfur from raw material gas through reaction with a portion of a hydrogen-containing gas.
2. Description of the Related Art
A fuel cell system that uses hydrocarbon as raw material gas (raw fuel gas) involves reforming the raw material gas by, for example, using steam in the presence of a reforming catalyst. The raw material gas contains a sulfur compound, which may have been added as an odorant or originate from the starting material from which the gas has been made. The sulfur compound, damaging to the reforming catalyst, needs to be removed from the raw material gas.
An example of a desulfurizer, a piece of equipment that removes sulfur from something, is a hydro-desulfurizer. The operation of a hydro-desulfurizer involves hydrodesulfurization, a process of allowing sulfur to react with hydrogen in the presence of a catalyst (Ni—Mo or Co—Mo) and then making the produced hydrogen sulfide adsorbed onto zinc oxide. To meet this need for hydrogen in hydrodesulfurization, a hydro-desulfurizer has a reformer that produces a fuel gas part of which is supplied to the desulfurizer (e.g., see Japanese Patent Application No. 2002-356308).
The technology described in this patent application, however, has room for improvement in terms of maintaining the efficiency of the hydrogen generator.